Boosting Ion Diffusion and Charge Transfer by Zincophilic Accordion Arrays to Achieve Ultrafast Aqueous Zinc Metal Batteries

Abstract

AbstractA key challenge to apply aqueous zinc metal batteries (AZMBs) as next‐generation energy storage device is to improve the rechargeability at high current densities, which is needed to circumvent slowly ion diffusion in anode and sluggish charge transfer of Zn2+. Herein, a zincophilic accordion array derived from MOF is developed as zinc host for simultaneously boosted ion diffusion and charge transfer. The designed host is prepared by etching and disproportionation reactions, the abundant zincophilic Sn sites with nano‐size uniform disperse on accordion arrays nanosheets (Sn‐AA). Then a composite Zn anode (Sn‐AA@Zn) is obtained by compacting Sn‐AA host with zinc power (Zn‐P). The Sn‐AA@Zn anode has an ultra‐low activation energy (37.1 kJ mol−1) and nucleation overpotential (10 mV), achieving fast charge transfer of Zinc deposition. In addition, the cycle life of the symmetric cell with Sn‐AA@Zn anode exceeds 13 000 cycles at 50 mA cm−2, which is 32 times than that of the Zn‐P anode. And the full cell with Sn‐AA@Zn anode and MnO2 cathode maintains a capacity of 122 mAh g−1 after 5000 cycles at 5 Ag−1. Hopefully, the 3D anode based on Sn‐AA@Zn accordion array and Zn‐P has significantly improved the rechargeability of AZMB at high current density.